Explosion-proof switch box assembly including reciprocal external actuator means



Aug. 2, 1966 J. J. FARINA ETAL 3,264,443

EXPLOSION-'PROOF' SWITCH BOX ASSEMBLY INCLUDING RECIPROCAL EXTERNALACTUATOR MEANS Filed Nov,. 18, 1963 7 @l ,3 o f HTTORNEY United StatesPatent O 3,264,443 EXPLOSION-PROOF SWITCH BOX ASSEMBLY IN- CLUDINGRECIPROCAL EXTERNAL ACTUA'IOR MEANS Joseph J. Farina, Bridgeton,Marshall G. Zavertnik, Manchester, and James A..Kelly, St. Louis, Mo.,assignors to Killark Electric Manufacturing Company, St. Louis, Mo., acorporation of Missouri Fiied Nov. 18, 1963, Ser. No. 324,398 10 Claims.(Cl. 200-172) The present invention relates to a switch box assembly andparticularly one that is designed to be explosionproof andweather-proof.

In general, the assembly includes an explosion-proof box in whichelectrical switches are mounted, with linearly operating actuators onthe outside of the box and extending through a wall by explosion-proofbushings, The box can be made of an aluminum casting of appropriate wallthickness to prevent and contain explosions. The box has the necessarynumber of threaded ports for conduits through which wire connections canbe brought into the box. Within the box are a plurality of switchmounting clips that can be easily attached to an inside wall of the box,and can hold the electrical toggle switches all in a line so that theiractuating means operate linearly in parallel directions. Consequently,the portions of the actuating means that extend from the inside to theoutside of the box are all parallel. The actuating means are identical.The actuating means can be locked in either position of the toggleswitches.

A principal object of the invention is to provide an assembly of thiskind that has maximum flexibility so that it can take a maximum numberof different combinations and arrangements of switches with a minimumnumber of parts. Specically, it is an object of the invention to providean assembly of this kind in which conventional toggle switches may beused and actuated from outs-ide of an explosion-preventing receptacle orbox. In this connection, it is an object to provide actuators that canpass from the outside of the box to the interiorly mounted toggleswitches, which actuators are of simple construction and yet which aredependable -in operation as well as fire-proof and explosion-proof.Another object is to provide such an arrangement in which any number ofactuators can be applied to a given sized box provided with any numberof switches mounted within the box by the simple expedient of fillingand tapping the box for the appropriatae number of actuators and switchmountings. A further object is to provide an assembly that can be puttogther and taken apart with ease.

Other objects will appear from the description to follow.

Referring to the drawings:

FIGURE l is a plan view of the switch box assembly;

FIGURE 2 is a similar plan view, but with the cover removed, exposingthe toggle switches within the box;

FIGURE 3 is an end view taken from the right end shown in FIGURES l and2;

FIGURE 4 is a transverse section taken approximately on the line 4-4 ofFIGURE 1 show-ing one of the switches in its outer position;

FIGURE 5 is a somewhat enlarged fragmentary view of the switch-operatingmeans shown in FIGURE 4, but with the switch operating means in itsinner position;

FIGURE 6 is a top view of one of the switch-locking brackets; and

FIGURE 7 is a bottom view of the bracket.

The box 10 is here illustrated as being made of an aluminum casting withwalls approximately one-half inch thick, so as to withstand explosions.Preferably the entire box is made in a single casting, with anupstanding ice round cover opening 11 that is internally threaded toreceive a round and threaded cover 12 that screws into the opening 11.The cover has a flange 13 projecting outwardly from its threadedportion, the flange engaging over a gasket 14. By this arrangement thecover may be threaded in place, compressing the gasket that with thethreads forms an explosion-proof joint. The cover can have appropriateradial ribs 15 forming means by which it can be turned to screw it orunscrew it. The box also can be provided with integrally cast attachingears or lugs 17 to receive screws by which it can be attached to anappropriate support. It may also have an appropriat-e number of threadedopenings 18, 19 and 20 into which wire-containing conduits may bescrewed so that wires maybe brought to the interior of the box forattachment to the switches.

In FIGURE 2, four switches 22, 23, 24 and 25 are illustrated as mountedin the switch box. Other numbers, of course, may be used as needed.

The switches are identical, so that a description of the switch 23 willsuice for all. It is provided with anges 27 and 28 at opposite endsadjacent its bottom. A spring clip 31 is secured by drive screws or thelike to the bottom of the box 10. This spring clip 31 has a hook end 32at one end and a similar hook end 33 at the other. However, the hook 33has an outwardly-extending linger grip end 34, that is joined to thehook end 33 by a hairpin bend, somewhat rounded to facilitateinstallation of the switch as will be evident. Pressing the linger end34 rmly toward the bottom of the box releases the hook from the iiange27 and permits the switch to be removed or installed. The switch has aconventional toggle arm 37 projecting out of its top side.

Thus it can be seen that the desired number of spring clips 31 can bemounted on the bottom floor of the box 10 by self-tapping screws andthen the switches can be readily clipped into place, aided if necessaryby depressing the outstanding finger'ends 34 on the clips. Once theswitches are in place, the overhanging ends of the clips hold themsecurely. Access to the interior of the box for all of the foregoing isreadily available because of the large size of the threaded opening whenthe cover 12 is removed.

Actuating means 38, 39, 40 and 41 are provided for actuating therespective switches 22, 23, 24 and 25 from the exterior of the box.These are all the same and description of the actuator 40 illustrated inFIGURES 4 and 5 will suffice for all of them.

The toggle arm 37 of the switch 23 moves to the left and right in thedrawings. An actuator rod 43 is slidably mounted in an elongated bushing44 that is threaded tightly into an opening in the wall of the box.These parts, as illustrated, are in a line to accord with the line ofoperating movement of the toggle arm 37. The bushing is of sufficientlength to provide flame suppression around the rod 43.

Inside the box, the rod 43 has a ilattened end 45, onto which a flattoggle bracket 46 is attached by a screw 47. The bracket 46 has arectangular hole 48, through which the toggle arm 37 extends. The edgesof the hole 48 that may Ialternately engage the toggle arm, aredepressed somewhat for better engagement of the toggle arm.

To reciprocate the rod 43 in and out, a handle 50 is attached onto areduced outer end portion of the rod 43, and retained by a snap-ring 51applied transversely to the rod, as indicated. A Walds Tru-Arc Bowed Etype retainer is satisfactory, and provides a secure, rigid, connectionof the handle.

The handle 50 tits through a hole S4 in a shelf 5S of a locking bracket56 show-n separately in FIGURES 6 and 7. The bracket has a vertical endwall secured against the outside of the wall of the box lll by theflange on the bushing 44, the mounting being stabilized against twistingby a screw 57. The bracket also has side walls S8 and 59 for giving isstability. In `addition to the large hole 54, through which the handlet) extends, the shelf 55 has a small hole 60. The handle 50 has aprojecting ledge 61 overlying the shelf 55, and provided with a hole 62.In assembling the present assembly, a box 10 of suicient size to receivethe desired number of switches is chosen. Usually the same box can beused for a number of switches such as one to four. The box can bedrilled and tapped as at 18, 19 and 20 for the appropriate arrangementof the conduits that are to bring the wires to the switches. Normallyeach box `will have at least two such tapped holes in it, the ones notto be used being plugged by threaded plugs that eliminate the flamehazard.

A mounting spring bracket 31 is fastened to the bottom of the box foreach of the switches to be employed. Then the switches are snapped intoplace, being retained by the clips 31. The wire connections should beattached to the switches before the actuators are mounted.

An appropriate number of actuators 39 are provided, the box beingreadily drilled and tapped for each desired actuator bushing 44. Alocking bracket 56 is placed onto each bushing 44 to he held in placewhen the latter is screwed in tightly. The bracket is stabilized by ascrew 57. The rod 43, tting through the bushing 44, with its handle 5t)in place, can then have its toggle bracket 46 secured on by the screw47.

If it becomes necessary to replace a switch, the operator removes thetoggle bracket 46, depresses the tongue 34 to release the spring clip,and then can remove the switch. It may be necessary to remove the middleswitches to get at the ones at the side. Replacement is equally easy,since a switch can be hooked under the Clip hook 32 and then-pressedagainst the hook 33, which yields to enable the switch to lock in place.

. In use of the equipment, the switches can be locked in either inner orouter positions. A lock can be passed through the aligned holes 60 and62 as shown in FIG- URE 4, to retain the switch in outer position. Alock can be passed through the aligned holes 54 and 62 as shown inFIGURE 5, to retain the switch in inner position.

The opening 54 has a generally rectangular shape, as shown in FIGURES 6and 7. It can limit reciprocal movement of the handle 50, therebypreventing injury to the switch by excessive force against the togglearm 37.

One of the features of the present invention is that -the parts areextensively standardized. All of the actuators can be identical, andthis is true whether the toggle switches be single-throw or double-throwsiwtches, or what combinations are employed. Also the arrangement lendsitself to the use of toggle switches, rather than torque' switches,which is an advantage from the standpoint of simplification ofequipment.

Various changes and modifications may be made within the process of thisinvention as will be readily apparent to those skilled in the art. Suchchanges and modifications are within the scope and teaching of thisinvention as defined by the claims appended hereto.

What is claimed is:

1. In an explosion-proof box assembly: a box having an access opening inone side, and a cover removably mounted on the box to close the opening;at least one switch mounted in the box, removal of the cover from theopening giving access to the interior of the box for the securing of theswitch therein; the switch having an element adapted to be actuated byreciprocal movement; an actuator for the switch extending acrossthe-switch between it and the opening in the box, including a rodextending through a hole in the wall of the box and movable into and outof the box; a handle on the rod, outside the box, larger than the hole,by which the rod may be' pressed into and withdrawn out of the box in astraight-line movement; means normally limiting the withdrawal movementof the rod, comprising a switchelement-engaging member removably securedto the end of the rod adjacent the switch, and adapted to embrace theswitch element to enable reciprocal movement of the handle and rod bothWays, to actuate the switch, and being removable to permit the switch tobe removed or installed in the box.

2. The assembly of claim 1, wherein there is a locking bracket on theoutside of the wall of the box adjacent the hole, and the bracket andhandle have cooperating means to receive a lock when the handle is ineach of its inner and outer positions. 3. The assembly of claim 2,wherein the locking bracket is removable from the `box to facilitateremoval of the rod from inside the box.

4. The assembly of claim 3, wherein the locking bracket has meanslimiting inward and outward movement of the rod, and cooperating meanswith the handle for receiving a lock for locking the handle in inner orouter position.

5. The assembly of claim 2, wherein a bushing is threaded into the holein the box from the outside surrounding the rod, and has a flangeengageable with the locking bracket to clamp the locking bracket againstthe wall of the box.

6. The assembly of claim' l, wherein the switch has ledges adjacent itsbottom, and the means for holding it in place comprises a spring clipsecured to the box, the clip having spring-like overhanging endsreleasably engageable over the ledges of the switch.

7. In a switch assembly, a box, a switch in the box having an operatingmember operable by back and forth movement; a rod slidably mountedthrough a wall of the box, means on the inner end of the rod engageablewith the switch operating member to move it back and forth uponreciprocation of the rod back and forth; a handfe on the rod outside thebox; a bracket on the box adjacent the handle, the bracket havinglimiting means limiting inward and outward movements of the handle androd, and openings in the handle and bracket to receive a lock to lockthe handle, and therefore the switch, in inner or outer position.

8. In a switch assembly, a box, a spring clip having a first hook at oneend and a second hook at the other end, the second hook having adepressible tongue that can be depressed to spread the hooks apart; theclip being secured to an inner wall in the box with the ends outstandingfrom the wall; a switch having opposite ledges, one engageable under theiirst hook, and the other engageable under the second hook to hold theswitch securely in place in the box, the second hook having a curvedtongue that cams the second hook around the ledge on the switch when theswitch is pressed against the second hook; and actuating means for theswitch including a member movably mounted through the wall of the boxand projecting outside the same to be accessible for operating theswitch.

9. In a switch assembly, a switch box, a switch actuator including arod; the box having a hole through a wall through which the rod passes,a bushing surrounding the rod and holding it for reciprocating movement,the bushing having threads on its outer surface threaded into the holeand an enlarged flange at one end; a locking bracket mounted over thebushing, having a hole receiving the bushing but smaller than theflange, whereby the bushing holds the bracket against the box, thebracket having a ledge with a main hole through it, a switch actuatorhandle having a portion extending through the hole to below the ledgeand there attached to one end of the rod; the hole being larger than thepart of the handle passing through it and the handle movement beinglimited by th-e ends of the hole in the ledge;

in place.

UNITED References Cited by the Examiner STATES PATENTS Brachti 200-172Hardage 20G-168 Blood 200--172 Bissell ZOO-168 McKitrick ZOO-169 XTaylor 200-172 X Kobryner 317-119 X Lasar 20G-*172 Johnson 317-120 XOTHER REFERENCES Millerwise, German printed application No. 1,147,287,

10 ROBERT K, SCHAEFER, Primary Examiner.

BERNARD A. GrLHEANY, KATHLEEN H. CLAFFY,

Examiners.

H. O. I ONES, Assistant Examiner.

7. IN A SWITCH ASSEMBLY, A BOX, A SWITCH IN THE BOX HAVING AN OPERATINGMEMBER OPERABLE BY BACK AND FORTH MOVEMENT; A ROD SLIDABLY MOUNTEDTHROUGH A WALL OF THE BOX, MEANS ON THE INNER END OF THE ROD ENGAGEABLEWITH THE SWITCH OPERATING MEMBER TO MOVE IT BACK AND FORTH UPONRECIPROCATION OF THE ROD BACK AND FORTH; A HANDLE ON THE ROD OUTSIDE THEBOX; A BRACKET ON THE BOX ADJACENT THE HANDLE, THE BRACKET HAVINGLIMITING MEANS LIMITING INWARD AND OUTWARD MOVEMENTS OF THE HANDLE ANDROD, AND OPENINGS IN THE HANDLE AND BRACKET TO RECEIVE A LOCK TO LOCKTHE HANDLE, AND THEREFORE THE SWITCH, IN INNER OR OUTER POSITION.